I have a 1997 with a 4.3, It's been running great with few problems and now has 105k miles. Yesterday it started fine but when I started driving it didn't want to shift out of first gear (4l60) when it did go to second it hit hard. I continued driving to see if it would shift but it wouldn't. I also notice that the speedometer stopped working and the engine was idling rough. Well I turned it off and it wouldn't start back up, it only cranks. There is no power to fuse # 20 Ignition, from reading the other forums it sounded like the ignition switch might have gone bad. I grabbed one from a junk yard since it was only 15 bucks but it still isn't firing. Do you know or have a wiring schematic? What could the cause be for no power be? Help please.

I have a 1997 with a 4.3, It's been running great with few problems and now has 105k miles. Yesterday it started fine but when I started driving it didn't want to shift out of first gear (4l60) when it did go to second it hit hard. I continued driving to see if it would shift but it wouldn't. I also notice that the speedometer stopped working and the engine was idling rough. Well I turned it off and it wouldn't start back up, it only cranks. There is no power to fuse # 20 Ignition, from reading the other forums it sounded like the ignition switch might have gone bad. I grabbed one from a junk yard since it was only 15 bucks but it still isn't firing. Do you know or have a wiring schematic? What could the cause be for no power be? Help please. More info/// I had repaired the trans a while ago and found the lead that goes to the speedometer sensor on it had been pinched under the trans mount, I cut and respliced the wires to make sure they weren't cut but I thing this may have shorted out at one point. Could this have shorted out the ECM? How can I test it with a test light, volt meter or do I have to use a scanner? Thanks. Nick B.

Salvage yard is not a good place to get a good 97 switch.
Better go new one and see what it does.

On the transmission shifting the speed sensor/or circuit will have to be working.
A good transmission capable scanner will give your the read out on all sensors and or transmission problems and or codes.
If it has codes post back code no.

For a wiring diagram of ign switch and transmission wiring you need a good factory repair manual or the all data sub.
http://www.alldata.com/products/diy/index.html